Padlocks in which a pair of locking members are slidably mounted for reciprocal movement into and out of respective notches in the heel and toe portions of a J-shaped shackle are well known in the art. See, for example, U.S. Pat. Nos. 3,475,930 and 3,979,931. U.S. Pat. No. 4,098,100 describes a laminated padlock having a pair of coplanar slides for double locking the shackle and also having a safety rotator which overlies the inner end of the lock barrel and drivingly connects it to the locking slides. This safety rotor is designed to prevent picking of the lock by means of a tool inserted through the key slot in the lock barrel.